Oil change intervals on track day cars.

General General Lotus Talk
1

I have read lots of theories on how often oil changes should take place on track day cars, ranging from every track day to just follow the normal service schedule. Does anyone have any engineering knowledge of the correct intervals rather than just pet theories?

I have little knowledge of what “wears” oil but I expect total engine revolutions of the engine has a big effect. I believe total engine revs and the number of starts are the big influences on the service lights on many cars. Given that, it is probably safe to assume the average rpm on track is twice that on the road, halving the mileage duration. Soak back temperatures may have an effect? I cannot see that operating temp would have an effect, it would be within normal range. At higher rpm the engine may often be beyond maximum torque, which would be good for the long chain molecules in the oil.

Contamination will be a function of total engine revolutions so fits with my “halving” guess.

Does anyone have a better theory?

2

I don’t have any formal engineering knowledge, but I have built and run a fair few track cars in my time.

I think oil is a lot better than people give it credit for, heat, revs and contaminants age it from what I have read and been told, and that sounds right to me. So the way I looked at it, is oil is cheaper than engines. I was always pretty hard on my track cars, the engines saw a lot of revs, for a fairly long time. Oil temps would always be 120 ish by the time i finished, which I know isn’t excessive, but in my mind, it was enough.

I would change the oil and filter on my track day cars probably every third track day. I would change the gearbox oil at that interval too. The gearbox oil in Toyota cars gets really hot with track use.

Just my 2p, hope it helps.

3

Totally agree Sean
But I’m more excessive, Engine oil every other trackday, with my average being about 175 miles per day so every 300-350 miles
I never remove black shitty oil (I don’t need to)
Like Sean says an oil change at less than £100 is a lot cheaper than an engine swop at many thousands

4

…do we have a discount with Opie oils?

5

I change the oil in my car frequently as well and it is always cystal clear when it comes out. I work in aerospace where the engines run hotter, harder and longer then anything we do. The oil can be turned to froth, settled and recirculated. The oil change intervals are nothing like the same, being orders of magnitude longer.

I may contact an oil company and see what they say.

6

I am getting some feedback from a major oil company. Nothing definite yet by the message so far is “the oil will last longer than you may expect”. How do they know what I expect?

My pet theory is that track usage halves the mileage for the oil. Just for the simple fact that track miles probably uses twice the engine revolutions of road use. Revs is what wears the oil(and engine) and pollutes the oil with fuel and combustion residuals. It may be a bit worse than half because the engine will be at full throttle most of the time, so more fuel is going in with each stroke, which contaminates the oil.

One question the oil company asked is how fast do track day engines wear compared to normal use? I have no factual answers to give. K series engines explode before they wear out, Toyota/Honda engines are pretty robust (I think).

I am not trying to cheap skate on oil changes, I just like to do things based on facts (one of the problems of being an engineer).

7

I did about 60 trackdays over 2 years before having a baby and i changed oil every 4 trackdays just because my front pads and i think my front tyres (888s at the time) lasted about 4 days so the car would just go in for a service and have it all done together,

Dave and Sean commenting above are miles better drivers than me so will work the consumables harder, tho having seen Sean’s precision heel toe skills in action it’s safe to say my gearbox takes more of a beating than his and if he’s changing his gearbox oil every 2 trackdays i should change mine every 2 laps lol

8

The oil company is interested in doing oil sample tests to get a better idea so I will be provding oil samples at the end of season (now), first fill and after one track day.

Pretty impressed thay want to do that. For various resaons I did not have an intensive last few track days (ice, rain, wishbones came loose). Anyone close to Derby (or can post specimen bottles) with a Yota power that has had a good work out. Ideally you have used Fuchs oil.